I noticed this bug too on my system. Looks like there is no framerate limiter, when the game is mimimized. It runs as fast as it can, until it hits the CPU limit (wich is possible, as there is no rendering done). In my case I kinda solved it with turning vsync of in the game and set the max fps to my monitors refresh rate. Then I forced warframe to use vsync in my gpu driver. Tested on: win 10 i9 10850k GTX 3090 (driver 465.89) Not ideal but works.